NCT02319837 · OUTCOME

Time to Resumption of Any Hormonal Therapy Following Suspension at Week 37 Due to Undetectable Prostate-specific Antigen (PSA)

Safety and Efficacy Study of Enzalutamide Plus Leuprolide in Patients With Nonmetastatic Prostate Cancer (EMBARK) · Source last updated 2026-07-09

Results reported by the registry submitting party. Population, time horizon, units and missing values must be read together.

Measure: MEDIAN
Unit: Months
Interval / dispersion: 95% Confidence Interval
Time frame: From treatment suspension at Week 37 until resumption of any hormonal therapy (up to Month 98)

What was measured

Undetectable PSA at 36 weeks was serum PSA levels \<0.2 ng/mL at Week 36. At Week 37, study treatment was suspended for participants whose PSA values were undetectable (\<0.2 ng/mL) at Week 36 as determined by the central laboratory. Study treatment may have been suspended only once (at Week 37) due to undetectable PSA and was reinitiated if subsequent central laboratory PSA values increased to ≥2.0 ng/mL for participants with prior prostatectomy or ≥5.0 ng/mL for participants without prostatectomy. The time to resumption of any hormonal therapy following suspension at Week 37 due to undetectable PSA was defined as the time in months between the date of treatment suspension at Week 37 due to undetectable PSA and the date that hormonal therapy was restarted.

Analysis population: All participants in the ITT population (randomly assigned to study treatment) who had treatment suspension.

Groups in this outcome

Enzalutamide + Leuprolide

Participants were randomized to receive enzalutamide capsules 160 milligrams (mg)/day, plus leuprolide 22.5 mg intramuscular or subcutaneous injection once every 12 weeks from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory prostate-specific antigen (PSA) evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.

Placebo + Leuprolide

Participants were randomized to receive placebo capsules once daily, plus leuprolide 22.5 mg intramuscular or subcutaneous injection once every 12 weeks from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory PSA evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.

Enzalutamide Monotherapy

Participants were randomized to receive enzalutamide capsules 160 mg/day from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory PSA evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.

Group identifiers and denominators belong to this outcome only. They may differ in another outcome or in safety reporting.

Analysis denominator · Participants

Group	Source count
Enzalutamide + Leuprolide	321
Placebo + Leuprolide	240
Enzalutamide Monotherapy	304

Reported measurements

Source class 1

Values in Months · Interval/dispersion: 95% Confidence Interval
Group	Value	Spread	Lower	Upper	Comment
Enzalutamide + Leuprolide	19.6	Not reported	17.2	22.3	Not reported
Placebo + Leuprolide	16.8	Not reported	14.3	17.1	Not reported
Enzalutamide Monotherapy	10.5	Not reported	8.9	11.5	Not reported

Source statistical analyses

Group order, estimate direction, methods and comments are retained. No treatment ranking is inferred.

ci Lower Limit
0.577
ci Num Sides
TWO_SIDED
ci Pct Value
95
ci Upper Limit
0.834
group Ids
OG000
OG001
non Inferiority Comment
Two-sided P-value was based on a stratified log-rank test by screening PSA, PSA doubling time, and prior hormonal therapy. Hazard ratio was based on a Cox regression model stratified by factors defined above and was relative to placebo + leuprolide with \< 1 favoring enzalutamide + leuprolide.
non Inferiority Type
OTHER
p Value
<0.0001
param Type
Hazard Ratio (HR)
param Value
0.693
statistical Method
Log Rank
ci Lower Limit
1.381
ci Num Sides
TWO_SIDED
ci Pct Value
95
ci Upper Limit
1.984
group Ids
OG001
OG002
non Inferiority Comment
Two-sided P-value was based on a stratified log-rank test by screening PSA, PSA doubling time, and prior hormonal therapy. Hazard ratio was based on a Cox regression model stratified by factors defined above and was relative to placebo + leuprolide with \< 1 favoring enzalutamide monotherapy.
non Inferiority Type
OTHER
p Value
<0.0001
param Type
Hazard Ratio (HR)
param Value
1.655
statistical Method
Log Rank

Complete source fields

analyses

ci Lower Limit
0.577
ci Num Sides
TWO_SIDED
ci Pct Value
95
ci Upper Limit
0.834
group Ids
OG000
OG001
non Inferiority Comment
Two-sided P-value was based on a stratified log-rank test by screening PSA, PSA doubling time, and prior hormonal therapy. Hazard ratio was based on a Cox regression model stratified by factors defined above and was relative to placebo + leuprolide with \< 1 favoring enzalutamide + leuprolide.
non Inferiority Type
OTHER
p Value
<0.0001
param Type
Hazard Ratio (HR)
param Value
0.693
statistical Method
Log Rank
ci Lower Limit
1.381
ci Num Sides
TWO_SIDED
ci Pct Value
95
ci Upper Limit
1.984
group Ids
OG001
OG002
non Inferiority Comment
Two-sided P-value was based on a stratified log-rank test by screening PSA, PSA doubling time, and prior hormonal therapy. Hazard ratio was based on a Cox regression model stratified by factors defined above and was relative to placebo + leuprolide with \< 1 favoring enzalutamide monotherapy.
non Inferiority Type
OTHER
p Value
<0.0001
param Type
Hazard Ratio (HR)
param Value
1.655
statistical Method
Log Rank

classes

categories
measurements
group Id
OG000
lower Limit
17.2
upper Limit
22.3
value
19.6
group Id
OG001
lower Limit
14.3
upper Limit
17.1
value
16.8
group Id
OG002
lower Limit
8.9
upper Limit
11.5
value
10.5

denoms

counts
group Id
OG000
value
321
group Id
OG001
value
240
group Id
OG002
value
304
units
Participants

description

dispersion Type

95% Confidence Interval

groups

description
Participants were randomized to receive enzalutamide capsules 160 milligrams (mg)/day, plus leuprolide 22.5 mg intramuscular or subcutaneous injection once every 12 weeks from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory prostate-specific antigen (PSA) evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.
id
OG000
title
Enzalutamide + Leuprolide
description
Participants were randomized to receive placebo capsules once daily, plus leuprolide 22.5 mg intramuscular or subcutaneous injection once every 12 weeks from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory PSA evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.
id
OG001
title
Placebo + Leuprolide
description
Participants were randomized to receive enzalutamide capsules 160 mg/day from Day 1. Study treatment continued uninterrupted in the absence of disease progression until the central laboratory PSA evaluation at Week 36. At week 37 study treatment was suspended for participants whose PSA values were undetectable at Week 36 and was reinitiated if subsequent PSA values increased to the threshold specified for reinitiation of study treatment. Participants with detectable PSA values at Week 36 continued treatment without suspension until permanent treatment discontinuation criteria were met.
id
OG002
title
Enzalutamide Monotherapy

param Type

MEDIAN

population Description

All participants in the ITT population (randomly assigned to study treatment) who had treatment suspension.

reporting Status

POSTED

time Frame

From treatment suspension at Week 37 until resumption of any hormonal therapy (up to Month 98)

title

Time to Resumption of Any Hormonal Therapy Following Suspension at Week 37 Due to Undetectable Prostate-specific Antigen (PSA)

type

SECONDARY

unit Of Measure

Months

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Preserved source evidence · Not medical advice